package com.stars.util.common;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * @author : Rocks
 * @version : 1.0
 * @date : 2022/12/5 23:15
 * @description : 验证码生成器
 */
public class Captcha {

    private static final char[] mapTable = {
        '2', '3', '4', '5', '6', '7', '8', '9',
        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
        'j', 'k', 'm', 'n', 'p', 'q', 'r', 's',
        't', 'u', 'v', 'w', 'x', 'y', 'z'
    };
    public static Map<String, Object> getImageCode(int width, int height) {
        Map<String,Object> returnMap = new HashMap<>();
        if (width <= 0) width = 120;
        if (height <= 0) height = 40;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        Graphics g = image.getGraphics();
        //生成随机类
        Random random = new Random();
        // 设定背景色
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        //设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 30));
        // 随机产生168条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 168; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        //取随机产生的码
        StringBuilder strEnsure = new StringBuilder();
        //4代表4位验证码,如果要生成更多位的认证码,则加大数值
        for (int i = 0; i < 4; ++i) {
            strEnsure.append(mapTable[(int) (mapTable.length * Math.random())]);
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            // 直接生成
            String str = strEnsure.substring(i, i + 1);
            // 设置随便码在背景图图片上的位置
            g.drawString(str, 13 * i + 30, 25);
        }
        // 释放图形上下文
        g.dispose();
        returnMap.put("image",getBase64String(image));
        returnMap.put("strEnsure", strEnsure.toString());
        return returnMap;
    }
    //给定范围获得随机颜色
    static Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255) fc = 255;
        if (bc > 255) bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

    static String getBase64String(BufferedImage img){
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        try {
            ImageIO.write(img, "jpg", stream);
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        }
        byte[] bytes = Base64.getEncoder().encode(stream.toByteArray());
        String base64 = new String(bytes);
        return "data:image/jpeg;base64,"+base64;
    }
}
